Dolomite: a low cost thermochemical energy storage material. Issue 3 (21st December 2018)

• Record Type: Journal Article
• Authors: Humphries, Terry D.; Møller, Kasper T.; Rickard, William D. A.; Sofianos, M. Veronica; Liu, Shaomin; Buckley, Craig E.; Paskevicius, Mark
• Is Part Of: Journal of materials chemistry. Volume 7:Issue 3(2019)
• Page Start: 1206
• Page End: 1215
• Publication Date: 2018-12-21
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c8ta07254j
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Reversible storage of carbon dioxide in dolomite using a catalyst allows viable thermal energy storage technology. Abstract : The thermal energy storage properties of dolomite, CaMg(CO3 )2, from three sources (commercial, mined, and synthetic) are investigated as a potential solid–gas thermochemical energy store for concentrating solar thermal power (CSP) plants. The reversible carbon dioxide release/absorption cycle can be used to store and release large quantities of thermal energy that can be harnessed near 550 °C. To enable carbon dioxide absorption, a novel molten salt eutectic NaCl : MgCl2 mixture was added to the dolomite, which proved effective. Curiously, the mined (unrefined) sample proved to have the best calcination/carbonation properties with a stable cyclic stability of ∼50 mol% CO2 over 10 cycles. A morphological investigation by scanning electron microscopy reveals the mined sample contains impurities ( e.g. quartz) that prevent detrimental agglomeration of dolomite and its reaction products (CaCO3 and MgO). High levels of porosity in the mined dolomite also provide short gas–solid reaction pathways during carbonation. A commercial dolomite source contained too many impurities, resulting in the formation of high levels of Ca2 SiO4 that acted as a Ca-sink, lowering CO2 capacity. Finally, a high purity synthetic dolomite sample displayed high levels of agglomeration and phase segregation, lowering reversible CO2 capacity, which was attributed to a lack of impurities that restrict agglomeration.